After expanding the best picture category to ten films, the Academy is using an instant run-off voting system where members rank their favorite films; politicians, take note. "Oscar oddsmakers have 'The Hurt Locker' and 'Avatar' in a virtual dead heat for best picture. So it's a sure bet that one of them will win on Sunday, right? Not necessarily. Voting for best picture – and tabulating those votes – isn't a simple case of majority rule. For one thing, with 10 nominees this year, it's more likely than ever that no film will receive 50 percent-plus-one of the vote: If 'Avatar' and 'Hurt Locker' are as close as believed, even if the other eight nominees combined drew, say, just 15 percent of the votes, that likely would be enough to keep either of the favorites from reaching 50 percent. In the past, that wouldn't have mattered: the top vote-getter would take the trophy, end of story. But this year, the Academy changed the script. When it expanded the best picture category from five nominees to 10, it also changed the voting system from a plurality (most votes wins) to something that sounds like a communicable disease – STV. It actually stands for the Single Transferable Vote system, and it's also known as Instant Runoff, Preferential Voting or Alternative Voting. Basically, instead of just selecting a favorite, each voter ranks all 10 nominees. The ballots are separated into 10 groups: those with 'Avatar' No. 1 in one group, those with 'Hurt Locker' as the top pick in another, and so forth. Then, if no film has a majority of No. 1 votes, the system goes to work."